Pressure-sensitive touch screen and touch display screen and electronic device

ABSTRACT

The present invention relates to a touch screen, and particularly to a pressure-sensitive touch screen and an electronic device. The present touch screen comprises a substrate which has an elastic deformation performance and is used by a user to operate and a strain sensor which is used for detecting lateral deformation of the substrate and is fixedly arranged at a peripheral location of a lower surface of the substrate, and further comprises a pressure bearing plate, wherein the pressure bearing plate is fixedly arranged at an upper surface of the substrate, and the location where the side edges of the pressure bearing plate are projected onto the strain sensor is located at a middle location of the strain sensor. Also provided is an electronic device containing the pressure-sensitive touch screen. By way of detecting a lateral deformation amount of the substrate, the present invention thus recognizes a touch location and a touch pressure value, provides a pressure-sensitive operation function for a user and can adapt to different input methods, without being limited by the touch form.

FIELD OF THE INVENTION

The present invention relates to touch screens, and more particularly toa pressure-sensitive touch screen, a touch display screen, and anelectronic device.

BACKGROUND OF THE INVENTION

Nowadays, touch screens can display digital information for computers orother data processing devices, and further provide intuitive input.Touch screens are also utilized in various electronic products, throughtouch screens, various functions such as data input, operation, andcontrol are achieved, and thus man-machine conversation is achieved too.In this way, much convenience is brought into production and life, andthe problem that input devices, for example, keypads and mice, areinconvenient to carry can be overcome.

In the current industry, various types of touch screens, such as thecapacitance type, the resistance type, the infrared type, and thesurface acoustic wave type touch screens, have already existed. Thesetouch screens detect touch location information by means of detectingthe changes of the touch capacitance/the touch resistance/the obstructedinfrared/the obstructed acoustic wave after a finger is applied. Thesetypes of touch screens can only obtain the location information of theusers' touch operations, but cannot detect a pressure value during atouch. In the actual use, when the touch pressure value needs to bedetected, these touch screens do not have any way to detect the value,and thus the application of the products is limited. Moreover, in theactual use, the precision of the detecting locations of these touchscreens are realized according to the electrical principles of the touchscreens. Therefore, the problem of low reliability occurs: since aresistance touch screen uses resistor film material as a part of itselectrodes, the soft film material is prone to be affected by scratchesand breaks, and thus the reliability will be greatly reduced; since acapacitance touch screen works according to the principle of detectingtiny capacitances, when liquid is splashed onto its surface or it is ina low temperature/high temperature condition, capacitance detectionerrors may occur frequently, even the touch screen may fail and itssystem may crash; other types of touch screens may also have similarproblems, and these problems directly cause low reliabilities of thetouch screens.

Furthermore, the existing touch screens are limited by input methods,for example, they may need to be directly touched by fingers withoutgloves, or need to be equipped with touch pens, which may bring muchinconvenience to users.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a pressure-sensitivetouch screen and an electronic device, which are configured to solve theproblems in the prior art that touch screens cannot detect touchpressure values, users cannot use the pressure-sensitive operationfunction, and the operation reliability is low.

The present invention is realized by the following technical solution: apressure-sensitive touch screen, which comprises a substrate which hasan elastic deformation performance and is configured to be operated by auser and at least one strain sensor which is configured to detectlateral deformation of the substrate and is fixedly arranged at aperipheral location of a lower surface of the substrate.

Preferably, each of the at least one strain sensor is connected inseries with a reference sensor which has the same specification andparameters as the strain sensor, and each of the reference sensor(s) isadjacent to its corresponding strain sensor and is arranged at anoutside of an edge of the substrate.

Preferably, the pressure-sensitive touch screen further comprises apressure bearing plate, wherein the pressure bearing plate is fixedlyarranged at an upper surface of the substrate, and the location wherethe side edges of the pressure bearing plate are projected onto thestrain sensor is located at a middle location of the strain sensor.

Preferably, the pressure-sensitive touch screen further comprises apressure bearing plate, wherein the pressure bearing plate is fixedlyarranged at an upper surface of the substrate, and the location wherethe side edges of the pressure bearing plate are projected onto thereference sensor is located at a middle location of the referencesensor.

Preferably, the strain sensor is uniformly distributed along thedirection of the periphery of the substrate.

Preferably, the strain sensor is arranged at four corners of thesubstrate. The present invention further provides a touch displayscreen, which comprises a pressure-sensitive touch screen; wherein, thepressure-sensitive touch screen comprises a substrate which has anelastic deformation performance and is configured to be operated by auser and at least one strain sensor which is configured to detectlateral deformation of the substrate and is fixedly arranged at aperipheral location of a lower surface of the substrate, and an uppersurface of the substrate of the pressure-sensitive touch screen isprovided with a display screen unit which has rigidity and is integratedwith the pressure-sensitive touch screen.

The present invention further provides another touch display screen,which comprises a pressure-sensitive touch screen; wherein, thepressure-sensitive touch screen comprises a substrate which has anelastic deformation performance and is configured to be operated by auser, at least one strain sensor which is configured to detect lateraldeformation of the substrate and is fixedly arranged at a peripherallocation of a lower surface of the substrate, and a display screen unitwhich has a rigid structure; the display screen unit is fixedly arrangedat an upper surface of the substrate, and the location where the sideedges of the display screen unit are projected onto the strain sensor islocated at a middle location of the strain sensor.

Preferably, each of the at least one strain sensor is connected inseries with a reference sensor which has the same specification andparameters as the strain sensor, and each of the reference sensor(s) isadjacent to its corresponding strain sensor and is arranged at anoutside of an edge of the substrate; the display screen unit is fixedlyarranged at an upper surface of the substrate, and the location wherethe side edges of the display screen unit are projected onto thereference sensor is located at a middle location of the referencesensor.

The present invention further provides an electronic device, whichcomprises any one of the aforementioned pressure-sensitive touch screensor any one of the aforementioned touch display screens.

Compared with the prior art, the present invention provides apressure-sensitive touch screen, a touch display screen, and anelectronic device, of which the strain sensor is arranged at theperipheral location of the substrate and is used to detect thehorizontal elastic deformation of the substrate and thereby identify thetouched location and the touch pressure value; thus, the touch input issupplied with an additional dimension, the pressure-sensitive operationfunction is more diversified, and various input methods can be applied.Since the operation for the touch screen is realized by detecting thestrain of the substrate generated by the touch pressure, the touchoperations of the users are not limited by the touch methods.Furthermore, the deformation of each strain sensor does not need to bedetected, and thus the assembly and connection requirements of thestrain sensor and the substrate are very low; in this way, thereliability and sensitivity of using the pressure-sensitive touch screenare improved. The above-described pressure-sensitive touch screen cansimultaneously detect the pressure value and the touched location whenbeing operated by a user, so that the pressure-sensitive operation ofthe touch screen is more diversified, and the convenience of operatingthe touch display screen and the electronic device is improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a rear of a pressure-sensitive touchscreen of a first embodiment of the present invention.

FIG. 2 is a partially and schematically cut-away view of thepressure-sensitive touch screen of the first embodiment of the presentinvention.

FIG. 3 is a partially and schematically cut-away view of apressure-sensitive touch screen of a second embodiment of the presentinvention.

FIG. 4 is a partially and schematically cut-away view of apressure-sensitive touch screen of a third embodiment of the presentinvention.

In the drawings, the corresponding relationship between numbers andcomponents are as follows:

-   -   1-strain sensor; 2-pressure bearing plate; 3-supporting plate;        4-substrate; 5-first metal wire; 6-second metal wire;        7-reference sensor; 8-third metal wire.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In order to make the objectives, technical solutions, and advantages ofthe present invention be clearer, the present invention will be furtherdescribed hereafter with reference to the accompany drawings andembodiments. It should be understood that the embodiments describedherein are only intended to illustrate but not to limit the presentinvention.

The realization of the present invention will be described hereafterwith reference to the accompany drawings.

As shown in FIG. 1 and FIG. 2, the present invention provides apressure-sensitive touch screen. In this embodiment, thepressure-sensitive touch screen includes a substrate 4 and at least onestrain sensor 1; the substrate 4 has an elastic deformation performanceand a high sensitivity, and can be operated by users; the strain sensor1 is fixedly arranged at a peripheral location of a lower surface of thesubstrate 4. When a user touches the substrate 4, the substrate 4generates lateral deformations along the direction of its touchedsurface, that is, the substrate 4 generates deformations along thelength direction and the width direction thereof. The strain sensor 1detects the amplitudes of the lateral deformations, and calculatesaccording to the amplitudes to obtain the location touched by the userand the pressure value.

Thus, the user's touch operation is supplied with an additionaloperation dimension, and a pressure-sensitive operation function isprovided to the user. Since the operation for the touch screen isrealized by detecting the strain of the substrate 4 generated by thetouch pressure, the operation is not limited by the touch methods, bothnon-conductive objects (e.g., pens, gloves, and so on) and conductiveobjects (such as fingers) can generate the touch effect, various inputmethods can be applied, and the deformation of each strain sensor 1 doesnot need to be detected. Thus, the assembly and connection requirementsof the strain sensor 1 and the substrate 4 are very low, and thereliability of using the pressure-sensitive touch screen is improved.

As shown in FIG. 4, each strain sensor 1 is connected in series with areference sensor 7, in this embodiment, each reference sensor 7 has thesame specification and parameters as its corresponding strain sensor 1.Thus, the design and assembly are facilitated, and the mass productionis easy to realize. Each reference sensor 7 is adjacent to itscorresponding strain sensor 1 and is arranged at an outside of an edgeof the substrate 4. In each strain sensor 1, one end of the strainsensor 1 is connected in series with a reference sensor 7 through asecond metal wire 6, and the second metal wire 6 is a signal measuringwire configured to measure signals; the other end of the strain sensor 1is connected to a voltage supply through a third metal wire 8, and theother end of the reference sensor 7 is connected to the ground through afirst metal wire 5. Since the location of each strain sensor 1 is veryclose to the location of the reference sensor 7 corresponding to thestrain sensor 1, and the two sensors have identical specification andparameters, the ambient environment generates similar interferences onthe two sensors. When a user touches and operates the substrate 4, thesubstrate 4 generates an elastic deformation; in particular, a portionof the strain sensor 1 contacting the substrate 4 generates a stretchdeformation, and a resistance Rm of the portion of the strain sensor 1contacting the substrate 4 increases; a portion of the reference sensor7 contacting the substrate 4 generates a compression deformation, and aresistance R of the portion of the reference sensor 7 contacting thesubstrate 4 reduces. A total resistance change detected by the strainsensor 1 is a sum of a resistance ΔRm generated by a stretch strain andan interference resistance Ri, and a total resistance change detected bythe reference sensor 7 is a sum of a resistance ΔR generated by acompression strain and the interference resistance Ri. Accordingly, thedifference between the two signals, that is, (ΔRm+Ri)−(ΔR+Ri)=ΔRm+ΔR,can offset the interference resistance Ri; and the strength of the touchsignal is increased, because the absolute value of the touch signalbecomes ΔRm+ΔR. In this way, interferences on the sensors, which aregenerated by environmental factors such as the temperature or thestress, can be offset. Of course, it is unnecessary that one of the twosensors 1 and 7 is positive and the other is negative, so long as thereis a big enough difference between the measurement ranges of the twosensors 1 and 7, the influence of the external environment can bereduced or eliminated by the difference detecting method, because theenvironment generates the same influences on the positive changingsection and the negative changing section generated by the elasticdeformation of the substrate 4. By means of the signal measurementthrough the second metal wire 6, the environmental interferences can beminimized. In this way, the pressure-sensitive touch screen provided bythe present invention identifies the touch pressure value and thetouched location on the one hand, and on the other hand, it is subjectedto little environmental interference during touch operations and is notlimited by the touch methods. Thus, the convenience and reliability oftouching the touch screen are improved, and the precision of detectingthe touch pressure is improved, too.

Furthermore, in this embodiment, the strain sensor 1 can be scanned andrecorded at a predetermined frequency, for example, the frequency can be60 Hz, and the touched location and the touch pressure value during eachscan are detected. In this way, the movement of the touched pointrelative to the time can be determined, and thus the touch gesture, thatis, the user's operation method, can be determined by predeterminedalgorithm. For example, when the touched location moves, along with thetime, from the right to the left, it is evident that the touch operationis a page turning action. Moreover, the touch pressure information canbe used to further define the meaning of the touch action, for example,when a page turning action is performed by a force exceeding a presetstandard, turning a plurality of pages by one page turning action can berealized. In this way, the users' operation methods for the touch screenare more diversified, and it is convenient for the users to betterrealize “human-computer interaction” with the touch screen.

Also referring to FIG. 2, FIG. 3, and FIG. 4, the pressure-sensitivetouch screen further includes a pressure bearing plate 2, the pressurebearing plate 2 is fixedly arranged at an upper surface of the substrate4, and users can operate the substrate 4 by touching the pressurebearing plate 2. In this way, the substrate 4 can be prevented frombeing directly touched by users, so that wear and contamination of thesubstrate 4 are reduced, and the service life is increased. Wherein, inthe first embodiment shown in FIG. 2 and the second embodiment shown inFIG. 3, the location where the side edges of the pressure bearing plate2 are projected onto the strain sensor 1 is located at a middle locationof the strain sensor 1. Wherein, in the third embodiment shown in FIG.4, the location where the side edges of the pressure bearing plate 2 areprojected onto the reference sensor 7 is located at a middle location ofthe reference sensor 7. In these designs, a touch pressure generatedduring a user's operation is reasonably distributed to the periphery ofthe substrate 4 by the pressure bearing plate 2, once the substrate 4generates a small lateral deformation, the periphery of the substrate 4will be drawn and deformed; thus, the strain sensor 1 can immediatelydetect the lateral deformation extent of the substrate 4, and thedetecting sensitivity of the pressure-sensitive touch screen isimproved. Preferably, the strain sensor 1 is uniformly distributed alongthe direction of the periphery of the substrate 4. Alternatively, thestrain sensor 1 is arranged at four corners of the substrate 4.

In particular, the pressure bearing plate 2 is fixedly arranged at anupper surface of the substrate 4 by means of glue, and can be used toinput information in response to touching operations of users.

As shown in FIG. 1, the strain sensor 1 is arranged at the periphery ofthe substrate 4, so that the central portion of the substrate 4 is notcovered.

Of course, the number of the strain sensors 1 at one side edge of thesubstrate 4 can be larger than the number of the strain sensors 1 at anyother side edge of the substrate 4 that is adjacent to the one sideedge. In specific application, the number of the strain sensors 1 can beincreased or decreased, and the number of the strain sensors 1 and thelocations of the strain sensors 1 can be determined according to varioustouch screen designs.

In the actual production, the pressure bearing plate 2 is made oftransparent material, such as glass, acrylic, or polycarbonate. Thesubstrate 4 can be made of transparent material or opaque material, forexample, a metal plate such as an aluminum plate or a stainless steelplate. In particular, the central portion of the substrate 4 is made oftransparent material, and the peripheral portion of the substrate 4 ismade of opaque material, the contents on the display screen under thesubstrate 4 can be observed through the central window portion of thesubstrate 4.

In particular, the strain sensor 1 is an electronic component made ofthin metal wires, polycrystalline or amorphous semiconductors, carbonnano-tubes, or conductor-insulator composites.

As shown in FIG. 2, each strain sensor 1 is connected to a detectingcircuit through a first metal wire 5 and a third metal wire 8 which arerespectively arranged at two ends of the strain sensor 1. Therelationship between a pressure of a user's touch and a lateral elasticdeformation of the substrate 4 meets Hooke's law, that is, conforms to alinear relation; the elastic deformation of the substrate 4 generates aresistance change accordingly, by detecting the resistance change, thedetecting circuit can obtain the elastic deformation extent of thesubstrate 4, and thereby obtain the touched location and the touchpressure value of the user's touch. In actual application, in both thelateral and longitudinal directions of the horizontal surface of thesubstrate 4, the strain sensors 1 are arranged in pairs, that is, inevery two parallel side edges of the substrate 4, a pair of strainsensors 1 are respectively arranged at the two parallel side edges,thereby forming a lateral channel and a longitudinal channel. When auser touches different locations, the substrate 4 generates elasticdeformations accordingly, and resistance changes are generated in thelateral channel and the longitudinal channel; by calculating theresistance changes generated by the substrate 4, the detecting circuitcan determine the lateral coordinates and longitudinal coordinates ofthe touched locations and the touch pressures. In particular, when anidentical location is touched, the greater the touch pressure, thegreater the lateral deformation of the substrate 4, and the greater theresistance change; and the smaller the touch pressure, the smaller thelateral deformation of the substrate 4, and the smaller the resistancechange. Different resistance changes correspond to different touchpressures, by collecting and calculating the resistance changes, thedetecting circuit can obtain precise touched locations and touchpressures. When the touch screen is not touched, the substrate 4recovers its original state due to its elasticity.

When two or more locations at the substrate 4 are touchedsimultaneously, the touched locations and the touch pressure values canalso be obtained by detecting the resistance changes generated by theelastic deformations of the substrate 4. In this way, a multi-touchoperation can be realized.

Moreover, the pressure-sensitive touch screen further comprises asupporting plate 3, which is arranged at a lower surface of thesubstrate 4, located at the outside of the periphery of the substrate 4,and positioned alternately with the strain sensor 1. The supportingplate 3 is fixedly arranged at the outside edge of the lower surface ofthe substrate 4, and a separation distance is formed between thesupporting plate 3 and the strain sensor 1. The supporting plate 3 isusually fixedly mounted at the periphery of the lower surface of thesubstrate 4 by means of glue. By setting the separation distance, thestrain sensor 1 is provided with a space allowing lateral movements.Thus, the elastic deformation of the substrate 4 is provided with aspace; when the substrate 4 generates a deformation, it is notobstructed by other components under the substrate 4, and does notinterfere with the adjacent supporting plate 3.

The present invention further provides a touch display screen, whichincludes any one of the above-described pressure-sensitive touchscreens, and the pressure-sensitive touch screen of the touch displayscreen includes the substrate 4 and the strain sensor 1; the uppersurface of the substrate 4 is provided with a display screen unit, thedisplay screen unit has rigidity, is not prone to deform, and isintegrated with the pressure-sensitive touch screen. In this way, themanufacturing process can be simplified, and the manufacturing cost canbe reduced.

The display screen unit can also be fixedly arranged under thesupporting plate 3, and a lower end of the supporting plate 3 is abuttedagainst the periphery of the display screen unit.

The present invention further provides another touch display screen,which includes any one of the above-described pressure-sensitive touchscreens, and the pressure-sensitive touch screen of the touch displayscreen includes a substrate 4, at least one strain sensor 1 fixedlyarranged at the peripheral location of the lower surface of thesubstrate 4, and a display screen unit which has a rigid structure; thedisplay screen unit is fixedly arranged at the upper surface of thesubstrate 4, and the side edges of the display screen unit are projectedon a middle location of the strain sensor 1 or a middle location of thereference sensor 7. In fact, the pressure bearing plate 2 of the touchscreen is replaced by the display screen unit having certain rigidity,such as an OLED display or a liquid crystal display. Using the displayscreen unit as the pressure bearing plate 2 can reduce the thickness andcost of the whole touch display screen.

Additionally, if the pressure bearing plate 2 is a resistive touchscreen, a capacitive touch screen, or a surface acoustic wave touchscreen, the touch display screen can directly provide the locationinformation, and the strain sensor 1 only needs to provide the touchpressure information. In this way, the touch display screen can use onlyone group of strain sensors 1, and thus the circuit design issimplified.

Additionally, the display screen unit can be embedded in the pressurebearing plate 2, and the display screen unit can also be integrated withthe pressure bearing plate 2. That is, the pressure bearing plate 2 hasa display function.

The present invention further provides an electronic device, whichincludes any one of the above-described pressure-sensitive touch screensor any one of the above-described touch display screen. By adopting, theabove-described pressure-sensitive touch screen, the pressure value andthe touched location of a user's operation can be simultaneouslydetected, so that the pressure-sensitive operation of the touch screenis more diversified, and the convenience of operating the electronicdevice is improved.

What described above are only preferred embodiments of the presentinvention, and are not intended to limit the scope of the presentinvention; and any modifications, equivalent replacements, andimprovements made within the spirit and principle of the presentinvention should be included in the protection scope of the presentinvention.

What is claimed is:
 1. A pressure-sensitive touch screen, comprising: a substrate configured to elastically deform upon being operated; and at least one strain sensor configured to detect lateral deformation of the substrate, the strain sensor being fixedly arranged at a peripheral area of a lower surface of the substrate; wherein the at least one strain sensor is connected in series with a reference sensor, the reference sensor having the same specification and parameters as those of the strain sensor, and the reference sensor is disposed adjacent to the strain sensor.
 2. The pressure-sensitive touch screen according to claim 1, further comprising a pressure bearing plate fixedly arranged at an upper surface of the substrate, at least a portion of an edge of the pressure bearing plate being on top of a central area of the strain sensor.
 3. The pressure-sensitive touch screen according to claim 1, wherein the reference sensor is arranged to be outside of an edge of the substrate.
 4. The pressure-sensitive touch screen according to claim 1, wherein one end of the reference sensor is connected to ground through a first wire, the other end of the reference sensor is connected with one end of the strain sensor through a second wire, and the other end of the strain sensor is connected to a voltage supply through a third wire.
 5. The pressure-sensitive touch screen according to claim 1, wherein, while the substrate elastically deforms, at least a portion of the reference sensor contacting the substrate is compressed by stretching at least a portion of the strain sensor contacting the substrate.
 6. The pressure-sensitive touch screen according to claim 1, further comprising a difference calculator that calculates a difference between resistance changes of the strain sensor and the reference sensor to thereby reduce the impact of an environmental factor on the strain sensor.
 7. The pressure-sensitive touch screen according to claim 1, further comprising a pressure bearing plate fixedly arranged at an upper surface of the substrate, at least a portion of an edge of the pressure bearing plate being on top of a central area of the strain sensor.
 8. The pressure-sensitive touch screen according to claim 7, wherein the pressure bearing plate comprises a transparent material.
 9. The pressure-sensitive touch screen according to claim 1, wherein plural strain sensors are uniformly distributed along a periphery of the substrate.
 10. The pressure-sensitive touch screen according to claim 1, wherein a strain sensor is arranged at each of four corners of the substrate.
 11. The pressure-sensitive touch screen according to claim 1, further comprising a detecting circuit electrically connected to the at least one strain sensor, the detecting circuit being configured to obtain a touched location on the substrate and a pressure value of a touch operated on the substrate by detecting a resistance change of the strain sensor in response to elastic deformation of the substrate.
 12. The pressure-sensitive touch screen according to claim 11, wherein the strain sensor is configured to be scanned at a predetermined frequency, and the detecting circuit is configured to detect a touched location on the substrate and a pressure value of a touch operated on the substrate for each scan of the strain sensor.
 13. The pressure-sensitive touch screen according to claim 12, wherein the detecting circuit is configured to detect a series of touched locations on the substrate and/or pressure values of a series of touches operated on the substrate to determine a touch action performed on the substrate.
 14. The pressure-sensitive touch screen according to claim 1, wherein at least one pair of strain sensors is arranged at two edges of the substrate opposing one another in a lateral direction, and at least another pair of strain sensors is arranged at another two edges of the substrate opposing one another in a longitudinal direction.
 15. The pressure-sensitive touch screen according to claim 1, wherein a central portion of the substrate comprises a transparent material, and a peripheral portion of the substrate comprises an opaque material.
 16. The pressure-sensitive touch screen according to claim 1, wherein the strain sensor comprises a thin metal wire, a polycrystalline or amorphous semiconductor, a carbon nano-tube, or a conductor-insulator composite.
 17. The pressure-sensitive touch screen according to claim 1, further comprising a supporting plate arranged outside of the peripheral area of the lower surface of the substrate, the supporting plate being positioned a predetermined distance from the strain sensor.
 18. A touch display screen comprising: the pressure-sensitive touch screen according to claim 1, and a display screen unit arranged at an upper surface of the substrate of the pressure-sensitive touch screen, the display screen being rigid, and being integrated with the pressure-sensitive touch screen.
 19. An electronic device comprising the pressure-sensitive touch screen according to claim
 1. 20. A pressure-sensitive touch screen, comprising: a substrate configured to at least laterally deform upon being touched; first and second strain sensors each disposed on a periphery of a lower surface of the substrate, the first and second strain sensors being laterally separated from each other, the first strain sensor changing resistance in response to lateral deformation of the substrate, the second strain sensor providing a reference resistance; and a detecting circuit electrically connected to the first and second strain sensors, the detecting circuit being configured to detect both a touched location on the substrate and a pressure value for a touch, based on the change in resistance of the first strain sensor in response to lateral deformation of the substrate and to use the resistance of the second strain sensor to compensate for changes in resistance of the first strain sensor due to environmental conditions. 